Thermal Paste Maintenance

I've recently cleaned all of the dust out of my 2009 Mac Pro with Isopropanol 99.9% and wanted to clean inside of the heatsinks too as I can see a lot of dust inside. I understand that when I take the heatsink off it will seperate the thermal paste from the processor, so will have to be reapplied. I have ArtiClean Thermal Material Remover, Thermal Surface Purifier and Arctic MX-4.

The machine is three years old and out of warranty, I was going to sell it but the low resale price has made it worth keeping so wanted to do some preventative maintenance. Other than the fact I would have to reapply the thermal paste when I take the heatsinks off, would you recommend reapplying it routinely anyway?

Correctly applied good quality thermal paste should be perfectly stable for a few years - I would speculate 3-5 years unless you really bake the processors.

You may have more luck giving the ends of the heatsinks a vacuum then buying a couple of cans of compressed air and blasting the heatsinks from one end without removing them. Your machine is only a few years old... how dirty is it?

The rest of it was pretty bad, it took me two days to clean. I use it mostly for 3D and will leave it rendering overnight quite a lot of the time, so it can be going full speed between 24 - 72 hours.

I wanted to do this firstly to clean all the dust out of the heatsinks and cpu fans, but also
check what state the current thermal paste is in, I don't have much faith in Apple's mass production attention to detail. I figure as long as I do it properly, I can't do it any harm and maybe improve it's thermal performance, as well as preventing any future damage from dust esd.

just make sure you're confident with taking off and putting back the heat sinks which can be a bit tricky, especially with the 2009 dual processor models. You'll find lots of threads around this (ie processor upgrade) if you search the forums

Also keep in mind it will take some time for the new thermal compound to be "broken in" (best way I can describe it). During this initial period expect slightly higher temps. I would leave the machine on for at least 12 hours to let the compound fill in all those microscopic groves.
Turn sleep off during this period.
I've built countless machines in the past, even did water cooling.

Make sure you get those heat sinks back on exactly the way they were before you took them off.

While you're at it, you may consider doing the same with your GPU + heatsink.

It's funny, I've been a tech/computer junky for 15 years and I found out TODAY in a youtube podcast by these guys that you should consider replacing the thermal paste every so often. (These guys say YEARLY!?)

Personally, I have never done this and have not ever had any issues, even with computers as old as a decade. My 2006 Mac Pro has probably been turned on (but in sleep mode mostly) for about 6 years straight with no issues. I don't notice increased processor fan RPM, but I admit I have not monitored temperatures.

I have a couple of related questions to this post, so thought I'd resurrect it rather than start a new one.

I've been researching exactly what I need to do to replace the thermal paste and read in the Mac Pro technicians manual that on a 8 core Mac Pro the processors are lid less and aren't held in place by a clamp. Consequently when I remove the heatsink the processor could be stuck to it with the thermal paste.

Does anyone have any advice on what would be the best way to clean the current thermal paste off the processor? Should I reseat it first? My only concern with this is that it isn't clamped in place and could move around while I'm cleaning it causing some damage to the sockets, or should I find a way of cleaning it separately? I suppose I'd have to find some way of suspending it, I presume placing it on a flat surface would cause damage to the underside. From what I've seen, it can take some effort to clean off old thermal paste.

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